v-erbA oncogene initiates ultrastructural changes characteristic of early and intermediate events of meiotic maturation in Xenopus oocytes
✍ Scribed by Sylvia B. Nagl; Caroline F. Bunn; Lizabeth A. Allison
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 655 KB
- Volume
- 67
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
The growth-promoting properties of the retroviral v-erbA oncogene, a highly mutated version of the chicken thyroid hormone receptor (TR) ␣, have so far exclusively been linked to dominant repression of the antimitogenic roles of TR and retinoic acid receptors. Here we show that when expressed in Xenopus oocytes v-ErbA induced ultrastructural changes characteristic of early and intermediate events of meiotic maturation by activating gene transcription. v-ErbA-induced maturation events occurred without activation of the cAMP/maturation-promoting factor signal pathway and were arrested prior to meiotic spindle formation. The effects of v-ErbA were not mimicked by a dominant negative in vitro-generated mutant of human TR, suggesting that v-ErbA can contribute to cell cycle reentry by interference with regulatory pathways distinct from those involving TR. Interestingly, a portion of v-ErbA expressed in oocytes was present at the cytoplasmic fibrils of the nuclear pore complexes, suggesting that in addition to its intranuclear function v-ErbA may modulate nucleocytoplasmic transport.